Suicide and drug overdose rates continued to rise in 2017, helping drive the number of U.S. deaths to the highest total in more than 100 years, the Centers for Disease Control and Prevention said in a series of reports on mortality released Thursday.

“Tragically, this troubling trend is largely driven by deaths from drug overdose and suicide," CDC Director Robert Redfield said in a statement. "These sobering statistics are a wake-up call that we are losing too many Americans, too early and too often, to conditions that are preventable."

Life expectancy in 2017 fell to an average of 78.6 years for the total U.S. population, down from 78.7 years in 2016.

Overall, more than 2.8 million Americans died in 2017, about 70,000 more than in 2016.

The reports noted that heart disease, cancer, unintentional injuries, chronic lower respiratory diseases and stroke remained the leading causes of U.S. deaths. Since 2008, suicide has ranked 10 and has grown at an alarming rate.

In 2016, suicide became the second-leading cause of death for ages 10-34 and the fourth-leading cause for ages 35-54.

Last year, 47,000 people committed suicide, a rate of 14 per 100,000 people. That is up from 10.5 in 1999 and from 13.5 last year. The total number of suicide deaths was the highest in a half-century and up more than 2,000 from 2016.

The 2017 numbers come despite the government's Healthy People 2020 goal to reduce suicide rates to 10.2 per 100,000 by 2020.

“We need to ensure that suicide prevention is ... tackled on the same scale and with the same vigor that we address other public health issues in this country,” said Bob Turner with the National Action Alliance for Suicide Prevention. Otherwise "the number of people dying by suicide or struggling with suicidal thoughts will continue to rise.”

Drug overdose deaths among U.S. residents exceeded 70,000 in 2017, nearly 6,600 more than in 2016, the CDC said. The rate has increased on average by 16 percent per year since 2014 and more than tripled since 1999.

"Deaths from drug overdose continue to be a public health burden in the United States," the CDC said, adding that "the pattern of drugs involved in drug overdose deaths has changed in recent years."

The rate of drug overdose deaths involving synthetic opioids other than methadone (drugs such as fentanyl, fentanyl analogs and tramadol) increased 45 percent in 2017 from the previous year. The rates of drug overdose deaths involving heroin, natural and semi-synthetic opioids and methadone were essentially unchanged from 2016.

“No area of the United States is exempt from this epidemic – we all know a friend, family member or loved one devastated by opioids,” said CDC Principal Deputy Director Anne Schuchat.

The CDC figures are based mainly on a review of death certificates in 2017. The life expectancy figure is based on death trends and other factors.

Life expectancy fell for the first time in decades in 2015. It held steady in 2016 but dipped again last year. The USA is seeing its longest overall downward trend since World War I.

CDC officials did not speculate about what’s behind declining life expectancy.

William Dietz, a disease prevention expert at George Washington University, sees a sense of hopelessness.

Financial struggles, a widening income gap and divisive politics cast a pall over many Americans, he suggested. “I really do believe that people are increasingly hopeless, and that leads to drug use, it leads potentially to suicide,” he said.

Drug overdose deaths continued to climb, although the death rate rose 10 percent from the previous year, smaller than the 21 percent jump seen from 2016 to 2017.

That’s not quite cause for celebration, said John Rowe, a professor of health policy and aging at Columbia University.

“Maybe it’s starting to slow down, but it hasn’t turned around yet,” Rowe said. “I think it will take several years.”

Other CDC findings:

•For males, life expectancy changed from 76.2 in 2016 to 76.1 in 2017. For females, life expectancy remained the same at 81.1.

•The infant mortality rate rose slightly, from 587 infant deaths per 100,000 live births in 2016 to 579.3 in 2017.

•Age-adjusted death rates increased for seven leading causes and decreased for one: cancer.